Compressible means for bushings



Nov. 7, 1961- R. F. MOYER 6 COMPRESSIBLE MEANS FOR BUSHINGS Filed Jan.25, 1961 I I INVENTOR. L" I l J ROBERT F/PAN/(L/N MOYER hill-ll -I| g 5MFMJM ATTORNEY tes Patent Ofice 3,007,746 Patented Nov. 7, 19613,007,745 COMPRESSIBLE MEANS FOR BUSHINGS Robert Franklin Mayer,Warwick, R.I., assignor to Harsco Corporation, Harrisburg, Pa., acorporation of Delaware Filed Jan. 25, 1961, Ser. No. 84,870 4 Claims.(Cl. 308-4) This invention relates to compressible means for bushingsand more particularly to means for compressing and thereby reducing theinside diameter of a liner in a die set.

One of the objects of the present invention is to provide a means foruniform circumferential reduction of the inside diameter of the liner ina die bushing.

Another object of the present invention is to provide a means forreadily replacing the liner in a die bushing.

And still another object of the present invention is to provide meansfor adjusting the internal diameter of the liner in a die bushingwhereby the mating relationship, between the liner and slidinglyengaging mating post, is adjusted especially in a manner to compensatefor wear.

In the conventional die set the upper or punch carrying plate isprovided with either two or four bushings located in the corner areas ofthe upper plate. The lower or die carrying plate is provided with eithertwo or four slidingly engaging or mating posts located in thecorresponding corner areas of the lower plate.

As the punch press, in which the die set is secured, reciprocates, theupper plate moves toward and away from the lower plate. This movementcauses the die bushings to slide up and down on the stationary post.This sliding movement of the bushing upon the mating post wears thebushing. The accuracy of the mating relationship is thereby destroyed.The accuracy of the mating relationship between the post and matingbushing determines the accuracy between the mating of the punch with thedie and therefore of the article produced by the punch and die. As thewear increases, the punch misaligns with the die until the wear andmisalignment become sufficiently great to cause a clash of the punchwith the die. Thus, the punch is broken; the die damaged and productionis stopped. The resulting economic loss is great.

It would appear to be a simple matter to provide a die bushing with areplaceable sleeve and liner when the bushing becomes worn and theaccurate mating relationship between the post and bushing is destroyed.However, such is not the case because the reciprocating movement of thepunch press causes heat to develop, due to friction, in both the postand mating bushing. The heat generated in the bushing causes the linerto freeze or bind to the bushing, thereby, destroying the purpose forwhich the liner was placed in the bushing. Namely, to be removed andreplaced when the inside diameter of the liner becomes worn.

As the punch and die mate during the work cycle, fine metallic dust andsplinters are created. The dust and splinters are created from theaction of the punch piercing the metal strip.

The dust and splinters find their way between the post and matingbushing. The heat generated by friction, the pressure of the punchpress, and the dust and splinters combine to reduce the space, clearanceor tolerance between the outside diameter of the post and the insidediameter of the bushing. Eventually the dust and splinter accumulationcauses gaulling and/or welding of the post to the bushing. The postbecomes frozen or jammed into the bushing. The punch press having apositive action, thereby causes an accident to the operative anddestruction to the very valuable punch and die.

The present invention was created to .obviate all of these undesirableand costly conditions in a die set by providing a liner which may bevaried as to its inside diameter and which may be removed from thebushing, regardless of the adverse conditions under which the die setfunctions.

Other objects of the present invention will become apparent in part andbe pointed out in part in the following specification and claims.

Referring to the drawings in which similar characters of referenceindicate corresponding parts in all the figures:

FIGURE 1 is a side elevational view of a conventional die set providedwith the new and improved compressible means for bushings.

FIGURE 2 is a vertical cross sectional View taken on line 2-2 of FIGURE1.

FIGURE 3 is an exploded perspective View of the new and improvedcompressible means for bushings.

FIGURE 4 is a bottom plan view of FIGURE 2 with the punch carrying plateremoved.

FIGURE 5 is a perspective view of a modified form of liner.

FIGURE 6 is a side elevational view of the new and improved compressiblemeans for bushings.

In proceeding with this invention reference is made to all figures inthe drawing. A die bushing fabricated of steel, generally indicated byreference numeral 10, consists of a cylindrical body 11. Internally, diebushing 10 is provided with a cylindrical axial bore 12, and acylindrical recess 13 which forms a cylindrical shoulder 14.

A cylindrical liner, generally indicated by reference numeral 15, isprovided with an outside diameter 16 and an inside diameter 17. Liner 15may be fabricated from bronze bushing material. The inside diameter ismanufactured with an extremely accurate dimension.

The inside diameter 17 of liner 15 slidingly engages the outsidediameter of post 18. When a post 18 having a one inch diameter is used,then the inside diameter 17 of liner 15 is between two ten thousandthsof an inch and five ten thousandths of an inch larger than the outsidediameter dimension of mating post 18.

When a post 18 having a three inch diameter is used, then the insidediameter 17 of liner 15 is between six ten thousandths and onethousandth of an inch larger than the outside diameter dimension ofmating post 118.

A cylindrical sleeve, generally indicated by reference numeral 25, isprovided with an outside diameter 26, a cylindrical bore 27, andopposite end faces 28, 29. A plurality of transverse clearance orifices30, 30A, 30B etc., are provided longitudinally in cylindrical sleeve 25.The clearance orifices 30 are illustrated as four in number but theycould be any plurality, two, three or more in number.

Cylindrical sleeve 25 is fabricated from elastic material, preferablyfrom the group of chemical compounds known as polyeurothane andespecially the material known as Elasta Cast. Such material permitscollar 25 to act as a compressible locking piece. As will presentlyappear, collar 25 is so constructed that, when means holding the sidesof collar 25 are tightened, the compressible locking collar 25 willexpand outwardly to frictionally engage axial bore 12. As axial bore 12sets up a resistance to the further expansion of compressible lookingcollar 25, said collar 25 contracts to frictionally grip and compressliner 15 through the engagement of bore 27 with outside diameter 16.

It is not enough that cylindrical sleeve 25' expand outwardly andcontract inwardly. The expansion and con traction must becircumferentially uniform. The inward action of compression must not beelongated or elliptical or act on one area of the inner circumferencewith greater force than another area. Many elastic or resilientmaterials will do just that when endwise thrust is applied to them.There are materials which react uniformly and Elastacast is one of them.

Two side or ring members 32, are provided; fabricated from rigidmaterial such as steel. Side or ring members 32, 33 are provided withcylindrical axial passageways 34, 35, respectively. Ring member 33 isprovided with clearance orifices, 36, 35A, 363, etc, axially alignedwith clearance orifices 3 ZQA, 39B, etc. Ring member 32 is provided withthreaded orifices 3'7, 37A, 373, etc., axially aligned with clearanceorifices 3h, 30A, 3913, etc. Bolts 38, 33A, 383, etc., are adapted topass tiu'ough clearance orifices and rotatively engage the re spectivethreaded orifices 37, 37A, 378, etc, whereby ring members 352, 33abutting end faces 29, 28, respectively, draw ring members 32, 33 towardor away from each other to apply more or less pressure upon elasticcylindrical sleeve 25. Liner 15 located in elastic cylindrical sleeve 25with outside diameter 15 engaging the wall of bore 27 and outsidediameter 26 engaging axial bore 12 are thereby subjected to the pressurecreated in elastic cylindrical sleeve 25.

The conventional die set comprises a punch carrying or upper plate 23provided with a stem 22 used as the fastening means of securing plate 23to the movable arm of a punch press (not shown); and a die carrying orlower plate 21 secured to the bed of a punch press (not shown). Diecarrying plate 21 is provided with a plurality of posts 18. Punchcarrying plate 23 is provided With an equal plurality of bores 24adapted to accommodate a plurality of mating bushings 16.

In assembling the component parts illustrated in FIG- URE 3 into theworking relationship shown in FIGURES 1, 2 and 6, liner 15 is placed inbore 27 with outside diameter 16 engaging the wall or surface of bore27.

Ring member 33 is placed in cylindrical recess 13 abutting cylindricalshoulder 14. Cylindrical sleeve 25 is placed in axial bore 12 with endface 28 abutting ring member 33 and thereby projecting beyond the end ofdie bushing 16'. Ring member 32 is then brought against end face 29. Thevarious clearance orifices 36, etc., Sit, etc.,and threaded orifices3'7, etc.,"are placed in lateral alignment so that bolts 38, etc., maypass through clearance orifices 36, etc., 3d, etc, and be rotativelyengaged with threaded orifices 37, etc., whereby ring members 32, 33squeeze or compress, endwise, cylindrical sleeve 25. Before thiscompression exceeds a very slight amount, the extended or exposed end ofcylindrical sleeve 25 is inserted into a bore 24- providcd in punchcarrying plate 23. Bolts 38 are then rotated to draw ring members 32, 33toward each other to compress compressible locking collar 25 an amountsufficient to expand said collar into a binding relation between outsidediameter 26 with axial bore 12 and bore 24. Punch carrying plate 23 anddie bushing are fabricated from steel. The walls of axial bore 12 andbore 24 act as a backstop for the expansion of compressible lockingcollar 25. Therefore, these walls stop the expansion of compressiblelocking collar 25 and convert the expansion into contraction as ringmembers are drawn toward each other. In this manner bore 27 contracts orsqueezes outside diameter 16 to grip liner 15. If this contraction orsqueezing action is suflioiently great, the inside diameter 17 will bereduced an amount permitted by the inherent resiliency of liner 25. In aliner 1S fabricated from bronze material the inside diameter 17 may bereduced as much as one thousandth (.001) of an inch. This amount issuificiently great to take up wear and to permit an adjustment betweenthe inside diameter 17 and the outside diameter of mating post 18. Thusthe economic life of the liner is prolonged and savings are made inmanufacturing costs used to create the critical mating relationshipbetween liner 15 and post 18. In addition the expansion and contractioncharacteristics of compressible locking collar permit the easy removalof said collar from axial bore 12 and bore .24; thus facilitating thereplacement of line 15 after it has become unduly Worn.

FIGURE 5 illustrates a liner 15A provided with a slit 5 which wouldpermit a reduction of more than one thousandth of an inch in insidediameter 17A. However, it will readily be observed that liner 15A couldbe squeezed an amount sufficient to cause inside diameter 17A to becomeoval in shape instead of concentric. This is an undesirable andunsatisfactory condition as inside diameter 17A must be concentric tothe outside diameter of post 1$for a satisfactory mating relationshiphaving a critical tolerance relationship.

Having shown and described a preferred embodiment of the presentinvention by way of example, it should be realized that structuralchanges could be made and other examples given without departing fromeither the spirit or scope of this invention.

What I claim is:

1. In a die set having in combination a punch carrying plate providedwith a plurality of bushing holding orifices and a cooperating diecarrying plate provided with a plurality of mating posts for aligningthe punch carrying plate with the die carrying plate, that improvementin said bushings which consists of a cylindrical body having acylindrical axial bore, a cylindrical liner having a cylindrical insidediameter and an outside diameter, a resilient cylindrical sleeveconsisting of a cylindrical bore, an outside diameter and opposite endfaces, said cylindrical liner located within said resilient cylindricalsleeve, a first ring member provided with a cylindrical axialpassageway, a second ring member provided with a cylindrical axialpassageway, said first and second ring members abutting, respectively,said opposite end faces, with said cylindrical axial passageways inaxial alignment with said cylindrical inside diameter, said first andsecond ring members fabricated from rigid material, said resilientcylindrical sleeve having one portion of said outside diameter locatedin one of said plurality of bushing holding orifices and the remainingportion of said outside diameter located in said axial bore and means tomove said first and second ring members toward and away from each other,whereby said outside diameter removably secures both said cylindricalbody to said punch carrying plate and said cylindrical liner to saidcylindrical axial bore.

2. In a die set having in combination a punch carrying plate providedwith a plurality of bushing holding orifices and a cooperating diecarrying plate provided with a plurality of matingposts for aligning thepunch carrying plate with the die carrying plate, that improvement insaid bushings which consists of a cylindrical body having an axial bore,a cylindrical liner having an inside diameter, and an outside diameter,a resilient cylindrical sleeve consisting of a bore, an outside diameterand opposite end faces, said cylindrical liner located within saidresilient cylindrical sleeve, a first ring member provided with an axialpassageway, a second ring member provided with an axial passageway, saidfirst and second ring members abutting, respectively, said opposite endfaces, with said axial passageways in axial alignment with said insidediameter, said first and second ring members fabricated from rigidmaterial, said resilient cylindrical sleeve having one portion of saidoutside diameter located 'in one of said plurality of bushing holdingorifices and the remaining portion of said outside diameter located insaid axial bore and means to move said first and second ring memberstoward and away from each other, whereby said outside diameter removablysecures .both said cylindrical body to said punch carrying plate andsaid cylindrical liner to said cylindrical axial bore, with the insidediameter of said cylindrical liner uniformly varying in diameter indirect proportion to the force exerted by said resilient cylindricalsleeve upon said cylindrical liner.

3. In a die set having in combination a punch carrying plate providedwith a plurality of bushing holding orifices and a cooperating diecarrying plate provided with a plurality of mating posts for aligningthe punch carrying plate with the die carrying plate, that improvementin said bushings which consists of a cylindrical body having an axialbore, a cylindrical liner having an inside diameter, and an outsidediameter, a longitudinal slit in said outside diameter, a resilientcylindrical sleeve consisting of a bore, an outside diameter andopposite end faces, said cylindrical liner located within said resilientcylindrical sleeve, a first ring member provided with an axialpassageway, a second ring member provided with an axial passageway, saidfirst and second ring members abutting, respectively, said opposite endfaces, with said axial passageways in axial alignment with said insidediameter, said first and second ring members fabricated from rigidmaterial, said resilient cylindrical sleeve having one portion of saidoutside diameter located in one of said plurality of bushing holdingorifices and the remaining portion of said outside diameter located insaid axial bore and means to move said first and second ring memberstoward and away from each other, whereby said outside diameter removablysecures both said cylindrical body to said punch carrying plate and saidcylindrical liner to said cylindrical axial bore, with the insidediameter of said cylindrical liner uniformly varying in diameter indirect proportion to the force exerted by said resilient cylindricalsleeve upon said cylindrical liner.

4. In a die set having in combination a punch carrying plate providedwith a plurality of bushing holding orifices and a cooperating diecarrying plate provided with a plurality of mating posts for aligningthe die carrying plate with the punch carrying plate, that improvementin said bushings which consists of a cylindrical body having an axialbore and an axial cylindrical recess forming a shoulder, a cylindricalliner having an inside diameter, and an outside diameter, a cylindricalsleeve fabricated from elastic material, consisting of a bore, anoutside diameter and opposite end faces, a plurality of clearanceorifices provided longitudinally in said cylindrical sleeve, saidcylindrical liner located within said cylindrical sleeve with saidoutside diameter engaging said bore, said cylindrical sleeve positionedwith portion of the outside diameter located in one of said plurality ofbushing holding orifices, and the remaining portion of the outsidediameter located in said axial bore, a first ring member having an axialpassageway and a plurality of clearance orifices axially aligned withsaid first mentioned clearance orifices, said ring member fabricated ofrigid material and located in said axial cylindrical recess and abuttingsaid shoulder and engaging one of said end faces, a second ring memberhaving an axial passageway and a plurality of tapped orifices axiallyaligned with the aforementioned clearance orifices, said ring memberfabricated of rigid material and axially aligned with said insidediameter and abutting the other of said opposite end faces, and aplurality of bolts located, respectively, in said plurality of clearanceorifices and rotatively mounted, respectively in said tapped orifices,whereby rotation of said studs moves said ring members toward and awayfrom each other to cause said cylindrical sleeve to expand outwardly toengage and be limited in expansion movement by said axial bore and saidbore and to contract to grasp and squeeze the outside diameter of saidcylindrical liner.

References Cited in the file of this patent UNITED STATES PATENTS2,405,825 Grunow Aug. 13, 1946 FOREIGN PATENTS 712,677 France July 27,1931 OTHER REFERENCES German printed application, 1,077,008, Mar. 3,1960.

